A construction working machine such as a front-end loader for digging holes or the like in residential or other areas is a hydraulic vehicle, and is constructed so that a hydraulic pump of a hydraulic drive mechanism is driven by a gasoline engine or a diesel engine to generate operating hydraulic pressure. Hydraulic working machines are often limited to nighttime use in residential and other areas due to engine noise.
Furthermore, working machines and vehicles driven by gasoline engines or diesel engines emit carbon dioxide. Air pollution from exhaust gas is currently a global issue and is a problem that requires an urgent resolution.
Therefore, it has been suggested that a hydraulic pump be driven using an electric motor in order to address the noise issue and to avoid air pollution from exhaust gas. However, a small-size, high-output power source suitable for mounting on a working machine is not currently available.